Etodolac is a nonsteroidal antiinflamatory drug (NSAID) that exhibits anti-inflammatory, analgesic, and antipyretic activities in animal models. Like that of other NSAIDs, the mechanism of etodolac is not completely understood, but is believed to be associated with an inhibition of prostaglandin biosynthesis. Etodolac is presently marketed by Wyeth-Ayerst Laboratories in the form of Lodine.RTM. tablets and capsules, which utilize a racemic mixture of etodolac.
U.S. Pat. No. 3,939,178 (Demerson et al.) teaches and claims certain pyrano3,4-B!indoles and thiopyrano3,4-B!indoles which include the (.+-.) 1,8-diethyl-1,3,4,9-tetrahydropyrano3,4-B!indole-1-acetic acid ingredient of Lodine.RTM. tablets and capsules.
The Physicians' Desk Reference, 49 Edition, 1995, at page 2682, teaches that etodolac is insoluble in water but soluble in alcohols, chloroform, dimethyl sulfoxide and aqueous polyethylene glycol.
U.S. Pat. No. 4,710,511 (Wooley) discloses a method of using etodolac compositions for inhibiting joint ankylosis for the treatment of arthritides. U.S. Pat. No. 4,742,076 teaches a method of using such compounds for lowering rheumatoid factor blood level. U.S. Pat. No. 4,966,768 (Michelucci et al.) describes a sustained release form of etodolac having as essential components etodolac, hydroxypropylmethylcellulose, ethylcellulose and a release rate modifying agent such as dibasic sodium phosphate, the hydroxypropylmethylcellulose having a hydroxypropoxyl content of about 7.0% to 8.6% by weight.
Demerson et al. disclose in the Journal of Medicinal Chemistry, 1983, Vol. 26, No 12, pp. 1778-1780, that biochemical and pharmacological tests showed that virtually all of the effects of etodolac are due to the S(+) enantiomer.
PCT application WO 93/17680 teaches methods and compositions utilizing optically pure R(-) etodolac for the treatment of pain. WO 93/17680 indicates that the optically pure R(-) etodolac substantially reduces certain purported adverse effects associated with the administration of the racemic mixture of etodolac.
Because of its unpleasant, bitter taste, etodolac has not, without some form of coating or taste-masking, been fully utilized in many formulations which would allow the etodolac to contact the recipient's taste buds. It is, therefore, significant that this invention provides organoleptically acceptable formulations containing uncoated and unmasked etodolac as an active ingredient. It is also significant that the production of the formulations of this invention do not require the additional formulation steps of coating the etodolac ingredient or incorporating taste masking ingredients into the formulations.